XHTML- A markup language for Web pages from the W3C. _ combines HTML and XML into a single format (HTML 4.0 and XML 1.0). Like XML, XHTML can be extended with proprietary tags and (also like XML) must be coded more rigorously than HTML. HTML expressed as valid XML. XHTML is to be used in the same places you would use HTML (creating web pages) but is much more strictly defined.
A network is a collection of computer systems configured to share digital data and resources.
Computer to computer :
Sender<-Channel->Receiver
Message-->Signal--->Message
Using “ping” or “traceroute,” you can discover the length of time that data is in transit
On average, data within the US usually arrives at its destination 110-120 milliseconds (ms) after it is sent
Overseas transmissions require a little more time
NetTraffic
Network Monitors-
Keep track of network traffic, number of packets, packet size, collisions, re-transmissions, etc.
Enable planning for growth and quality
Network Analyzers-
Randomly dissect packets, analyze problems, and determine the source of errors
Web entry stations that offer quick and easy access to a variety of services
Consumer portals include search engines, e-mail services, chat rooms, references, news headlines, shopping malls, and other services
Corporate portals on intranets serve the employees of particular corporations
Vertical portals are targeted at members of a particular industry or economic sector
Other Web Stuff
Push (auto-updates) versus Pull (browser in client-server model) technology
Provides access to a wide range of services and specialized peripheral devices
Enables people to work together, regardless of time and place
Network 101
Network Topography
May be physical or logical
Physical Topography
relates to a core network whereas logical topology relates to basic network
the physical design of a network including the devices, location and cable installation
Logical Topography
refers to how data is actually transferred in a network as opposed to its physical design
Client/server
Contains servers and clients
Peer-to-peer
every computer is considered an equal
network
a collection of computer systems configured to share digital data and resources
types
computer-to-computer
LANs (Local Area Networks)
Connectivity supporting two-way communication
Resource sharing
They extend across limited Geographical area
Servers, terminals, etc
Transparency of use
Support from hardware and software
Positives
communications
management control
cost-effectiveness
Negatives
need for additional equipment
maintenance
support staff
The defining characteristics of LANs, in contrast to wide area networks (WANs),
usually higher data-transfer rates
smaller geographic area
lack of a need for leased telecommunication lines
WAN (Wide Area Network)
a telecommunication network that covers a broad area (i.e., any network that links across metropolitan, regional, or national boundaries).
Business and government entities utilize WANs to relay data among employees, clients, buyers, and suppliers from various geographical locations.
In essence this mode of telecommunication allows a business to effectively carry out its daily function regardless of location
OFTEN OWNED BY SINGLE CORP
MAN (Metropolitan Area Network)
a computer network that usually spans a city or a large campus.
It interconnects a number of local area networks (LANs) using a high-capacity backbone technology, such as fiber-optical links
It provides up-link services to wide area networks (or WAN) and the Internet.
PAN (Personal Area Network)
a computer network used for communication among computerized devices, including telephones and personal digital assistants
It can be used for communication among the personal devices themselves (intrapersonal communication), or for connecting to a higher level network and the Internet (an uplink)
Nets
Intranets--collection of private computer networks within an organization
Extranets--computer network that allows controlled access from the outside for specific business or educational purposes.
Networking:
-Packet Switching:
The message is made of separate data packets, each addressed to the destination
Packets are transmitted over any available connection to the destination
The receiving node reassembles the message
Connecting:
-Modem / Dial-up
“modem” = modulate-demodulate
-Modulation – changing the characteristics of a signal (digital to analog)
-Demodulation – changing the signal back to its original state (analog to digital)
Cables:
-Most networks use twisted-pair cables
UTP (unshielded twisted pair)
STP (shielded twisted pair)
Looks similar to telephone cable
Has a square plastic RJ-45 connector
-Twisted Pair Wire Cable
Insulated pairs of wires historically used in telephone service
Category 1 – Telephones
Category 3 – Up to 10Mbps
Category 5 – Up to 100Mbps
-Another option is coaxial cable
Resembles cable-TV cable
Round, silver BNC or F-type connector
-Coaxial Cable (BNC)
Consists of an inner conductor wire surrounded by insulation, called the dielectric. The dielectric is surrounded by a conductive shield, which is surrounded by a non-conductive jacket. Coaxial cable has a better data transmission rate than twisted pair.
-Fiber-optic cable is a bundle of extremely thin tubes of glass
Many extremely thin fibers of glass or plastic, coated with a cladding and bound together in a sheathing which transmits signals with light beams
Fast transfer rates
Immune to electrical interference (emi occurs over long distances)
Hard to tap into
Takes less space
Each optical fiber (tube) is thinner than a human hair
Networks:
-Repeaters
boost the signal strength over transmission medium
-Bridges
isolate LANs from unnecessary traffic, but connect LANs to neighboring networks
-TCP/IP: Internet protocol suite is the set of communications protocols used for the Internet and similar networks, and generally the most popular protocol stack for wide area networks.Provides end-to-end connectivity specifying how data should be formatted, addressed, transmitted, routed and received at the destination
-IP address: is a numerical label assigned to each device (e.g., computer, printer) participating in a computer network that uses the Internet Protocol for communication.An IP address serves two principal functions: host or network interface identification and location addressing.
-An IP address is a series of numbers, such as 204.127.129.001
-Domain names are pseudonyms for IP addresses
-Protocols:
A communications protocol is a set of rules for efficiently transmitting data from one network node to another
The best-known protocol is probably TCP/IP
-Sending Computer:
Breaks the data into packets; adds addressing information; prepares the data for transmission
-Receiving Computer:
Takes packets off the cable; strips the packets of addressing information; reassembles the data from the packets
-TCP/IP provides a standard that is public, free, extensible, and fairly easy to implement. TCP/IP is the glue that holds the Internet together.
-ISPs need static IP addresses
-Numbers are hard to remember, so host computers also have names called domain names; a domain names corresponds to an IP address; domain name system – huge database that houses the names and IP addresses of key computers
-Domain name servers – computers that house this database
Internet 2-
consortium of government, industry, and education
The consortium-
establishes network capabilities to support national research
develops the next generation of Internet applications
transfers these to worldwide Internet
Internet 2-
remote instrumentation and virtual laboratories
distance learning
digital libraries
Tele-immersion
multicasting
National LambdaRail-
High-speed national network running on fiber
LambdaRail will merge with I2
Testing service network
University-based and -owned initiative
Wireless
infrared broadcasting
radio frequency broadcasting
spread spectrum (cell telephony)
direct sequence spread spectrum (DSSS)
frequency hopping spread spectrum (FHSS)
Networking article Vocabulary words: http://lis3353.wikispaces.com/Lab+A8+-+Networking+Terminology+Glossary
XHTML-
A markup language for Web pages from the W3C. _ combines HTML and XML into a single format (HTML 4.0 and XML 1.0). Like XML, XHTML can be extended with proprietary tags and (also like XML) must be coded more rigorously than HTML.
HTML expressed as valid XML. XHTML is to be used in the same places you would use HTML (creating web pages) but is much more strictly defined.
A network is a collection of computer systems configured to share digital data and resources.
Computer to computer :
Sender<-Channel->Receiver
Message-->Signal--->Message
Network Monitors-
Network Analyzers-
Web entry stations that offer quick and easy access to a variety of services
Other Web Stuff
Nets-
layers
layers
Nets
Networking:
-Packet Switching:
Connecting:
-Modem / Dial-up
- “modem” = modulate-demodulate
-Modulation – changing the characteristics of a signal (digital to analog)-Demodulation – changing the signal back to its original state (analog to digital)
Cables:
-Most networks use twisted-pair cables
UTP (unshielded twisted pair)
STP (shielded twisted pair)
Looks similar to telephone cable
Has a square plastic RJ-45 connector
-Twisted Pair Wire Cable
Insulated pairs of wires historically used in telephone service
Category 1 – Telephones
Category 3 – Up to 10Mbps
Category 5 – Up to 100Mbps
-Another option is coaxial cable
Resembles cable-TV cable
Round, silver BNC or F-type connector
-Coaxial Cable (BNC)
-Fiber-optic cable is a bundle of extremely thin tubes of glass
Networks:
-Repeaters
boost the signal strength over transmission medium
-Bridges
isolate LANs from unnecessary traffic, but connect LANs to neighboring networks
-TCP/IP: Internet protocol suite is the set of communications protocols used for the Internet and similar networks, and generally the most popular protocol stack for wide area networks.Provides end-to-end connectivity specifying how data should be formatted, addressed, transmitted, routed and received at the destination
-IP address: is a numerical label assigned to each device (e.g., computer, printer) participating in a computer network that uses the Internet Protocol for communication.An IP address serves two principal functions: host or network interface identification and location addressing.
-An IP address is a series of numbers, such as 204.127.129.001
-Domain names are pseudonyms for IP addresses
-Protocols:
A communications protocol is a set of rules for efficiently transmitting data from one network node to another
The best-known protocol is probably TCP/IP
-Sending Computer:
Breaks the data into packets; adds addressing information; prepares the data for transmission
-Receiving Computer:
Takes packets off the cable; strips the packets of addressing information; reassembles the data from the packets
-TCP/IP provides a standard that is public, free, extensible, and fairly easy to implement. TCP/IP is the glue that holds the Internet together.
-ISPs need static IP addresses
-Numbers are hard to remember, so host computers also have names called domain names; a domain names corresponds to an IP address; domain name system – huge database that houses the names and IP addresses of key computers
-Domain name servers – computers that house this database
Internet 2-
consortium of government, industry, and education
The consortium-
establishes network capabilities to support national research
develops the next generation of Internet applications
transfers these to worldwide Internet
Internet 2-
remote instrumentation and virtual laboratories
distance learning
digital libraries
Tele-immersion
multicasting
National LambdaRail-
High-speed national network running on fiber
LambdaRail will merge with I2
Testing service network
University-based and -owned initiative
Wireless
infrared broadcasting
radio frequency broadcasting
spread spectrum (cell telephony)
direct sequence spread spectrum (DSSS)
frequency hopping spread spectrum (FHSS)